Phenyl phosphonic acid esters



2,992,265 PHENYL PHOSPHONIC ACID ES'IERS Gerhard Schrader, Wuppertal-Cronenberg, Germany, as-

signor to Farbenfabriken Bayer Aktiengesellschaft,

Leverkusen, Germany, a corporation of Germany No Drawing. Filed June 18, 1958, Ser. No. 742,746

Claims priority, application Germany June 24, 1957 16 Claims. (Cl. 260-461) The present invention relates to and has as its objects new and useful insecticidal phosphonic acid esters which generally may be represented by the following formula S OR;

which are known from the literature (e.g. from U.S. Patent No. 2,503,390).

It has been found that these phenyl-thionophosphonic acid alkyl ester chlorides react with 2 mols of alkali hydroxide in such a manner as to form the hitherto not yet described phenyl-thionophosphonic alkyl ester acids of the following general formula:

(II) Rl wherein R stands for any substituted alkyl radical and R for an alkyl radical, preferably with 1 to 4 carbon atoms. These phenyl-thionophosphonic acid alkyl ester acids again react in their tautomeric form with any alkyl halides to form phenyl-phosphonic acid-O-alkyl-S-alkyl esters (III) which have likewise not yet been described in literature:

S CR 0 CR 0 OR; all 2 l Ra OH SH sRa (III) In these formulae R and R have the above mentioned significance, whilst R denotes any alkyl radical which may also be substituted.

Some of the new esters are distillable under vacuum without decomposition. They distinguish themselves by an outstanding insecticidal action. They may be used in the same manner as other known phosphoric insecticides, i.e. in a concentration from about 0.00001% to about 1%, diluted or extended with suitable solid or liquid carriers or diluents. Examples of such solid carriers are talc, chalk, bentonite, clay and the like, as liquid carriers there may be mentioned, water (if necessary with commercial emulsifiers), alcohols, especially lower alcohols such as methanol or ethanol, ketones, especially lower ketones such as acetone or methyl ethyl States Patent 0 ketone, liquid hydrocarbons and the like. The new com pounds may furthermore be used in combination with each other or with known insecticides, fertilizers etc.

As an example for the special utility of the inventive compounds the ester of the following formulae (III) 0 O C2 5 have been tested against spider mites. Aqueous solutions of the aforementioned compounds have been prepared by admixing them with the same amount of an auxiliary solvent (acetone). A commercial emulsifier (benzyl hydroxy diphenyl polyglycol ether) is added in an amount of 20% referred to active ingredient. This premixture then is diluted with water to the desired concentration.

The tests have been carried out in the following manner: against spider mites (contact-insecticidal action). Bean plants (Phaseolus vulgaris) of about 15 inches height are sprayed drip wet with solutions as prepared above. The bean plants have been infested heavily with the two-spotted spider (species Tetranychus telarius). Evaluation has been carried out after 24 hours, 48 hours and 8 days. The total percentage of killed pests after 8 days is to be seen from the following table:

solutions, killing compound percent rate,

percent I 0. 01 IT 0. 1 100 III 0. 01 100 56 grams of phenyl-thionophosphonic acid ethyl ester chloride (B.P. 75 C./0.01 mm. Hg) are dissolved in 125 millilitres ofanhydrous alcohol. 30 grams of water are added with stirring and then dropwise a solution of 29 grams of potassium hydroxide in 60 millilitrw of Water. The mixture is heated with further stirring to about 70 C. for another hour. 32 grams of monochloracetic acid ethyl ester are then added dropwise at an internal temperature of 75 C. The reaction temperature is maintained at 75-80 C. for a further 2 hours, the reaction product is then cooled to room temperature and poured into 200 millilitres of water. The precipitated oil is taken up with 300 millilitres of benzene. The benzenic layer is washed twice with 30 millilitre portions of water. The benzenic solution is dried over sodium sulfate. After fractionating 41 grams of the new ester of B.P. C./0.0l Hg are obtained. Yield: 57% of the theoretical. Solutions of 0.1% kill caterpillars completely. Aphids and spider mites are killed completely with solutions of 0.01%. Toxicity on rats per os LD 250 mg./kg. Systemic action on spider mites with 0.1% solutions 100%.

Example 2 56 grams of phenyl-thionophosphonic acid ethyl ester chloride are dissolved in 130 millilitres of anhydrous ethyl-alcohol. 30 millilitres of water are added to the solution and then a solution of 29 grams of potassium hydroxide in 60 millilitres of water. The solution is heated to 75 C. for an hour and 50 grams of 4-chlorophenyl-a-chloromethyl thioether (B.P. 91 C./1 mm. Hg) are added at 75-80 C. with vigorous stirring. The reaction product is then heated to 80 C. for a further 2 hours and Worked up as described in Example 1. 74 grams of the new ester are thus obtained as a pale yellow water-insoluble oil. Yield: 83% of the theoretical. The ester is undistillable even under high vacuum. Spider mites are killed completely with solutions of 0.01%. 0.1% solutions kill caterpillars completely. Toxicity on rats per os LD 500 mg./ kg.

Example 3 O OC2H5 56 grams of phenyl-thionophosphonic acid ethyl ester chloride are dissolved in 130 millilitres of anhydrous alcohol. 30 millilitres of water are added and then a solution of 29 grams of potassium hydroxide in 60 millilitres of water. The solution is heated to 70-75 C. for an hour and 47 grams of a-bromopropionic acid ethyl ester are added with stirring. The mixture is heated with further stirring to an internal temperature of 80 C. for a further 2 hours and then worked up as described in Example 1. 56 grams of the new ester of B.P. 113 C./0.0l Hg are thus obtained. Yield: 74% of the theoretical. Aphids, spider mites and caterpillars are killed completely with solutions of 0.1%. Toxicity on rats per os LD 100 mg./kg.

Example 4 57 grams of phenyl-thionophosphonic acid ethyl ester chloride are dissolved in 130 millilitres of anhydrous alcohol. 30 millilitres of water are added with stirring and then a solution of 29 grams of potassium hydroxide in 60 millilitres of water. The solution is heated to an internal temperature of 75 C. and 50 grams of 3.4- dichlorobenzyl chloride are added dropwise. After keep ing the reaction product at an internal temperature of 70-80" C. for a further 2 hours, it is worked up as described in Example 1. 42 grams of the new ester of B.P. 145 C./0.01 mm. Hg are thus obtained. Yield: 46% of the theoretical. Caterpillars are killed completely with solutions of 0.1%. Toxicity on rats per os LD 1000 mg./kg.

Example 5 O S-CH2-COOC2H5 Q -P 69 grams (0.3 mol) of phenyl-thionophosphonic acid methyl ester chloride are dissolved in 250 millilitres of methanol and 250 millilitres of water. A solution of .37 grams of potassium hydroxide (0.6 mol) in millilitres of water is added thereto at 70 C. The mixture is kept at the aforesaid temperature for an hour and 41 grams (0.3 mol) of ch-loracetic acid ethyl ester are then added dropwise at 60 C. The reaction product is kept at 60 C. for another hour and then worked up in usual manner. 32 grams of the new ester are thus obtained as a colorless water-insoluble oil of B.P. -l20 C./ 0.1 mm. Hg. Yield: 35% of the theoretical. Aphids and caterpillars are killed completely with solutions of 0.1%. 0.01% solutions kill spider mites completely. Toxicity on rats per os LD 500 rug/kg.

Example 6 (I) OCaHs 57 grams of phenyl-thionophosphonic acid ethyl ester chloride are dissolved in millilitres of alcohol. 30 millilitres of water are added to the solution and then, at 60 C., a solution of 29 grams of potassium hydroxide in 60 millilitres of water. The internal temperature is maintained at 70 C. for 2 hours and 42 grams of pchlorobenzyl chloride are then added dropwise with further stirring. The reaction product is kept at 75 C. for a further 2 hours and then worked up in usual manner. 55 grams of the new ester are thus obtained as a colorless water-insoluble oil which is not distillable even under high vacuum. Yield: 67% of the theoretical. Aphids are killed completely with solutions of 0.1%. 0.01% solutions kill spider mites completely. Toxicity on rats per os 1000 rug/kg.

Example 7 57 grams of phenyl-thionophosphonic acid ethyl ester chloride are dissolved in 125 millilitres of anhydrous alcohol. After the addition of 30 millilitres of water, a solution of 29 grams of potassium hydroxide in 60 millilitres of water are added with stirring at 70 C. The mixture is kept at a temperature of 70 C. for a further 2 hours and 32 grams of benzyl chloride are then added dropwise with further stirring. The product is then worked up in usual manner. 5 8 grams of the above ester are thus obtained as a pale yellow water-insoluble oil. Yield: 97% or the theoretical. Aphids and caterpillars are killed completely with solutions of 0.1%. 0.01% solutions kill spider mites completely. Toxicity on rats per os LD 500 mg./kg.

Example 8 57 grams of phenyl-thionophosphonic acid ethyl ester chloride are dissolved in 125 millilitres of alcohol. 30 millilitres of water are added thereto and then a solution of 29 grams of potassium hydroxide in 60 millilitres of water. The mixture is heated to 75 C. for 2 hours and 75 millilitres of dodecyl iodide are then added. The reaction product is kept at 75 C. for a further 2 hours and then worked up in the usual manner. 58 grams of the new ester are thus obtained as a pale yellow waterinsoluble oil. Yield: 63% of the theoretical. Aphids and spider mites are killed completely with solutions of 0.1%. Systemic action on spider mites with solutions of 0.1% 100%. Toxicity on rats per os 1 000 mg./kg.

Example 9 O OCH;

55 grams of phenyl-thionophosphonic acid methyl ester chloride are dissolved in 130 millilitres of methanol. 30 millilitres of water are added thereto and then a solution of 29 grams of potassium hydroxide in 60 millilitres of water. After heating to 70 C. for 2 hours, 32 grams of benzylchloride are added. The reaction product is kept at 70-75" C. for a further 2 hours, then diluted with 300 millilitres of benzene, cooled and washed with 100 millilitres of water. The benzenic layer is separated off, dried over sodium sulfate and fractionated. 48 grams of the new ester of RP. 122 C./0.'01 mm. Hg are thus obtained as a water-insoluble colorless oil. Yield: 69% of the theoretical. On rats per es the new ester shows a mean toxicity of 500 mg./ kg.

Example 10 S OCaHi II/ 221 grams of phenyl thionophosphonic acid ester chlo ride are dissolved in 500 millilitres of aceto nitrile. While stirring there are added 50 millilitres of water and subsequently a solution of 120 grams of KOH in 200 millilitres of water. The temperature is allowed to rise to about 70 C. and is kept there for 1 hour. The solvents then are distilled off and the residue is taken up in 800 millilitres of anhydrous alcohol. The undissolved KCl is removed by filtration with suction, and the clear alcoholic solution is concentrated. There is obtained a white crystalline reaction product which may finally be dried. There are obtained'167 grams of the above shown salt i.e. 70% of the theoretical.

Example 11 0 O CzHa 60 grams of the potassium phenyl thionophosphonic acid ethyl ester are dissolved in 100 millilitres of aceto nitrile. While stirring there are added at about 50 C. 18 grams of chloroacetic nitrile. This temperature is kept for about 1 hour and the reaction mixture then is poured into 200 millilitres of ice-water. The oil which separates is taken up in 200 millilitres of benzene. After drying the solvent is removed by distillation in vacuum. The remaining residue is undistillable even in high vacuum and is separated from lower distilling impurities at 1 Hg at a temperature of 70 C. within 1 hour. There are obtained 35 grams of the above shown new ester i.e. 58% of the theoretical. Toxicity on rats per os 25 mg./kg.

By exactly the same way but using 39 grams of w-ChlO- roaceto phenone (dissolved in 50 millilitres more of acetonitrile) there are obtained 62 grams of the new ester of the following formula which shows a toxicity on rats per os of 100 mg./kg.

Again by the same way but using 40 grams of a-chlorm methyl thiophenyl ether there are obtained 72 grams of the new ester of the following formula ll @"K s-cm-sQ which shows a toxicity on rats per os of 100 mg./kg.

Example 12 (6/0 C2Hs SCH I \SCH:-

60 grams of the potassium phenyl thionophosphonic acid ethyl ester are dissolved in 100 millilitres of acetonitrile. At C. there are added while stirring 47 grams of 2-a-ohloromethyl l-methyl mercapto-4-methylbenzene). The reaction product in this case is kept for 1 further hour at 80 C. and further working up may be carried out as described in the foregoing example. There are obtained 5 8 grams of the new ester of the above shown formula as a viscous water-insoluble oil, i.e. 66% of the theoretical. Toxicity on rats per os 250 mg./kg.

I claim:

1. Phenyl phosphonic acid-O-alkyl-S-alkyl esters of the following general formula Rui wherein R stands for a phenyl radical, R stands for lower alkyl radicals up to 4 carbon atoms, and R stands for a member selected from the group consisting of alkyl radicals of about 12 carbon atoms, lower carbalkoxysubstituted lower alkyl radicals, cyano-substituted lower alkyl radicals, phenyl mercapto lower alkyl radicals,

3. The phenyl phosphonic acid-O-alkyl-S-alkyl ester of the following formula 0 OCzH 4. The phenyl phosphonic acid-O-alkyl-S-alkyl ester of the following formula 0 OC2H5 5. The phenyl phosphonic acid-O-alkyl-S-alkyl ester of the following formula \s-om-Q-m 6. The phenyl phosphonic acid-O-alkyl-S-alkyl ester 13. The phenyl phosphonie acid-O-alkyl-S-alkyl ester of the following formula I of the following formula s-cm-ooomm 002m OCH: s-om-s-Q 7. The phenyl phosphonic acid-O-alkyl-S-alkyl ester of the following formula 0 00211,, 14. The phenyl phosphonic acid-O-alkyl-S-alkyl ester l of the following formula 0 OCH soHr -o1 G {V 2 5 SICHZ 8. The phenyl phosphonic acid-O-alkyl-S-alkyl ester of the following formula 0 002m Q P s-on 9. The phenyl phosphonic acid-O-alkyl-S-alkyl ester A Rhgnyl Phosphomc acld'o'alkyl's'alkyl ester of of the following formula the following formula 0 OR 3 P serum 10. The phenyl phosphonic acid-O-alkyl-S-alkyl ester f the f ll i f l wherein R is a lower alkyl radical having up to four 0 O CH carbon atoms and R is phenyl. a 16. A phenyl phosphonic acid-O-alkyl-S-alkyl ester of the following formula s-CHQ 0 OR:

ll/ 11. The phenyl phosphonie acid-O-alkyl-S-alkyl ester of the following formula 35. 501111! 0 002B! wherein R is a lower alkyl radical having up to four carbon atoms and R is a chloro-substituted phenyl STCHPGN radical. 12. The phenyl phosphorn'e acid-Oalkyl-S-alkyl ester 40 of the following formula References Cited 1n the file of this patent 0 001m Pudovik et al.: Chem. Abst., 49, column 8789 @JV 1955 M1chalsk1: Chem. Abst., 51, columns 4266-7 (March 25, 1957). 

1. PHENYL PHOSPHONIC ACID-O-ALKYL-S-ALKYL ESTERS OF THE FOLLOWING GENERAL FORMULA 